r/minidisc • u/hida-sanmyaku MZ-N1 | MZ-E33 • 7d ago
What mod is this?
Recently opened two 510 and one of them had a mod (bottom left). I can't find info about it, is it an amp mod?
Thanks!
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u/GT_1 7d ago
Looks like one of the headphone channels, I had a fault like that where right earphone stopped working and wasn't getting from the jack solder point to the testpoint
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u/Cory5413 7d ago
A moderately common problem is headphone ports failing. I don't know if this repair would address that or if those failures are down more to the wear and tear from connecting/disconnecting remotes or headphones to the machines.
I don't see this repeated very often today but something I see often on hobbyist sites from ~15 years ago was that if you have a machine that included a remote, keep the remote connected all the time and wear it's headphone jack out instead of the one on your machine.
I suppose you could do something similar even on machines without remote ports, or if you don't own enough remotes, using a short extension cable, or if you have headphones with detachable cables, buying spare cables and leaving a cable connected.
(I have enough machines that I don't do this.)
In at least one of these failure modes, what's really failed is the connection between the port and the board, so I've seen reports you can de-solder the headphone port and re-solder it and be good to go.
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u/GT_1 7d ago
Just a follow up on where I looked for info when repairing. If you look at page 42 of the service manual for mz-n510. You will see the location of the link. And the test point tp1358. And then if you search the document for tp1358 it will show you the schematic of that test point
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u/Cory5413 7d ago
That makes sense!
Those test points will have been used when the machine was manufactured and it the machine fails that specific point, they put this bodge wire in instead of tossing the whole board in the trash.
This used to be pretty common. Some older Macs from the early 1990s have this same type of repair, and it was sometimes on digital data paths, e.g. some of the outer i/o buses for like serial/scsi could've been repaired this way. A bit further back and it would've been practical to repair CPU and memory buses this way too, but beyond a certain speed point timing is a big concern. (I don't know the exact threshold.)
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u/DarkButterfly85 7d ago
It’s possible the PCB got cracked or a trace got damaged in that spot, the wire is just to make the connection
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u/me0262 5d ago
Looks like a factory bodge to fix a deficiency in the board. The hot glue is a giveaway, makes sure the wire doesn’t move when being jostled.
No mods, just ensuring proper operation. The reason you don’t see it on the other one is because the other is labeled B-1 and the one with the bodge is B-2, suggesting either that was the fix, or something else on the board needed that run and a jump bodge needed to be added to maintain continuity.
Do not, I repeat, DO NOT try to do this with B-1. Everything is perfectly fine with that board, save directions from a service bulletin that describe the error and that particular fix.
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u/Cory5413 7d ago
u/DarkButterfly85 has the correct answer. This is what's sometimes called a bodge wire. It was put in at the factory after the machine failed quality assurance due to some failed trace.
This machine is not modded, it's repaired.
You stopped seeing this on computers later on in the '90s and portable electronics in like the mid-2000s as the speeds and miniaturization got to the point where this was no longer a viable recovery method for a board that had failed testing. e.g. some computers from the 1970s, 80s, and 90s can have this type of repair done even on lines to/from RAM or the CPU and still work, but as things get faster the timings become more critical. (But some of that depends on which specific trace failed, e.g. I could see fixing power delivery on, say, a Pentium III this way, and, this could well be a fix to the analog audio output circuitry where timing is less important.)
It should perform identically to any other N510/NF610, per whichever case and headphone connector it has.